Method for controlling a knee orthosis

ABSTRACT

A knee orthosis and a method for controlling a knee orthosis including a thigh structure having a fastening structure to be fixed to a thigh, a lower leg structure which is pivotally coupled to the thigh rail using a joint mechanism and has a fastening structure to be fixed to a lower leg as well as a foot piece for supporting a foot, and an actuator device between the thigh structure and the lower leg structure. The fastening points of the actuator on the thigh structure and lower leg structure and the center of rotation of the joint mechanism form a triangle. The fastening points are arranged on the structures such that the connecting line between the fastening points extends perpendicular to a connecting line between a fastening point and the center of rotation in an angular position of the knee in which the lower leg is bent at an angle ranging from 0° to 90° relative to the thigh.

The invention relates to a knee orthosis with a thigh structure, inparticular a thigh rail, which has a fastening means for securing to athigh, with a lower leg structure, in particular a lower leg rail, whichis coupled pivotably to the thigh structure via a joint mechanism andhas a fastening means for securing to a lower leg, and, if appropriate,a foot part for supporting a foot, and with an actuator unit between thethigh structure and the lower leg structure, and a method forcontrolling such a knee orthosis.

Knee orthoses are used to support or replace a function of a leg. Theorthoses form an outer frame or partial frame and are applied to theleg. In cases of injuries to the ligaments or muscles, and in cases ofparalysis, orthoses serve to stabilize the joint and, if appropriate, tolimit the flexion angle or extension angle of the parts of the limbconnected via the knee joint. Generally, the knee orthoses have a railfor the thigh and a rail for the lower leg, and they are secured to thethigh and lower leg by fastening means, such as buckles or straps.

In cases of paralysis of the leg or corresponding injuries, provision ismade for the foot also to be fixed within the orthosis. For thispurpose, a foot shell is provided which is secured to the lower legstructure or is formed thereon.

DE 601 22 483 T2 describes a dynamic, electromechanical orthosis devicewith a wrap spring clutch which, on the basis of data from sensors thatare arranged in the plantar area of the foot shell, releases the jointmechanism between the thigh part and the lower leg part. A kinematicsensor is likewise provided that generates an electrical signal, whichis determined on the basis of the relative position and movement of thethigh structure to the lower leg structure. This signal is used tomonitor whether a wrap spring is actuated or released.

DE 10 2006 012 716 A1 describes a joint mechanism with which a movementabout an axis is released or blocked. A sensor device is provided thatmeasures forces, moments and/or angle position of the upper and lowerparts to each other and is coupled to a control unit which, as afunction of the measured parameters, activates an actuator and braces aspiral spring in order to block or release the joint.

DE 202 17 355 U1 describes an orthosis for external supporting andguiding of a knee joint, with a heel and foot part arranged on a lowerleg structure, which is connected to a thigh structure via a jointmechanism. A locking mechanism is provided, which can be actuated bymeans of the force of the foot and activates the locking mechanism whenthe foot is set down.

DE 299 14 375 U1 describes an orthosis joint with a thigh rail and alower leg rail which at one end engage with each other via one or morecommon pins or by means of teeth in the orthosis joint. End stops arepresent in the orthosis joint and are adjustable across an angle range.Upon flexion or extension in the orthosis joint, a constant or dynamicbraking action can be performed, which takes place pneumatically,hydraulically or by means of an elastic element. The braking action iseffected in particular via elastic stops.

DE 600 15 384 T2 describes a support device that replaces the existenceor function of a limb and is composed of at least two parts connected toeach other by an artificial joint, and a control device for the joint. Asensor is provided that detects an angle of inclination relative to afixed line of a part connected to the joint. The sensor is coupled tothe control device, which is arranged in such a way that it influencesthe joint on the basis of data transmitted by the sensor and relating tothe angle of inclination. In addition to a prosthesis, the supportdevice can also be designed as an orthosis.

The in some cases very complex devices take up a lot of space,particularly in the mediolateral orientation. The object of the presentinvention is to make available a knee orthosis which, in addition tohaving sufficient functionality, can also provide an improved cosmeticquality.

According to the invention, this object is achieved by a knee orthosishaving the features of claim 1 and by a method for controlling a kneeorthosis having the features of claim 18. Advantageous embodiments anddevelopments of the invention are described in the respective dependentclaims.

The knee orthosis according to the invention with a thigh structure,which has a fastening means for securing to a thigh, with a lower legstructure, which is coupled pivotably to the thigh structure via a jointmechanism and has a fastening means for securing to a lower leg, and, ifappropriate, a foot part for supporting a foot, and with an actuatorunit between the thigh structure and the lower leg structure, ischaracterized in that the fastening points of the actuator unit, on therails, and the center of rotation of the joint mechanism form atriangle, and the fastening points are arranged on the rails in such away that the connecting line between the fastening points isperpendicular to a connecting line between a fastening point and thecenter of rotation in an angular position of the knee in which the lowerleg is bent at an angle of between 0° and 90°, in particular 10° and90°, preferably between 30° and 90°, relative to the thigh. Thedistances between the fastening points of the actuator unit, on therails, and the center of rotation of the joint mechanism are fixed.However, by means of a relative movement of the fastening points to oneanother, on account of the pivoting of the thigh structure relative tothe lower leg structure, the length of the actuator unit, for example ofa hydraulic damper or of a hydraulic drive, changes. By means of asuitable arrangement of the fastening points on the rails, it ispossible to provide the knee orthosis with moment characteristicsdependent on the knee angle even with a constant damping of the linearactuator unit. This happens through a lever length being arranged andconfigured at a defined angle to the normal of the other rail, forexample the lever on the lower leg structure in relation to the normalof the thigh structure which passes through the center of rotation ofthe joint mechanism. The corresponding angle determines how theeffective lever length for the actuator or damper changes depending onthe knee angle. In this way, it is possible to set the knee angle atwhich the obtainable resistance moment or the transmissible forces areat a maximum. This results in a suitable profile of the force orresistance moment with a non-linear relationship, such that thebiomechanical lever ratios allow maximum leg support to be achieved whenthe leg is flexed, wherein the force applied by the actuator can be leftconstant. Maximum leg support thus occurs when the load on the jointmechanism or on the knee joint is very great, for example at an angle ofthe thigh to the lower leg of 35° to 45°. However, provision is alsomade for the maximum resistance moment or the maximum actuator force tobe made available at a lesser or greater flexion, insofar as this isnecessary or is desired by the patient. On account of the non-linearprofile of the resistance moment despite a constant damping in theactuator unit, a progressive damping is obtained, particularly in thearea of the stance phase flexion, and therefore a progressive stancephase damping, which can be produced without complicated controlmechanisms and sensor technology if the actuator is designed as alinearly acting damper. The same applies to the design of the actuatoras a drive. A progressive profile of the resistance moments in thestance phase flexion is described as comfortable by the patient, since aspontaneous buckling of the knee joint need not be feared.

In a development of the invention, the actuator is a hydraulic damper,and the valves or control means of the hydraulic damper are arranged infront of and/or behind a piston/cylinder arrangement in the direction ofwalking. With this arrangement of the valves and control means and alsoof the overflow channels, it is possible to make available a damper thathas a relatively narrow shape, such that the components do not protrudemuch in the mediolateral orientation. This leads to increased acceptanceof the orthosis, since the latter can be worn under normal clothing. Theactuator unit is designed in particular as a linearly acting damper, asa result of which the entire knee orthosis can be produced more easilyand more economically.

The actuator unit is preferably arranged laterally alongside the thighor lower leg, preferably alongside the thigh, with an arrangement behindthe rails of the orthosis in the direction of walking being preferred.In this way, the hydraulic mechanism can be subjected to pressurewithout deflection means, and the arrangement of the fastening points ofthe actuator on the rails permits easy adaptation to the desired momentcharacteristics. For example, several fastening points can be arrangedon one rail, in order thereby to be able to individually adapt themoment characteristics.

In a development of the invention, the actuator unit is mounted, atleast at one fastening point, via a bearing with at least two degrees offreedom. Provision is specifically made that the actuator is mounted, atleast at one fastening point, via a cardan bearing with intersecting ornon-intersecting axes. Because of the individual configuration of therespective orthosis, which has to be adapted to the patient, there arealignment errors in the movement axes, both in terms of the joint axisand also of the axes at the fastening points, such that the cylinder ofthe actuator unit moves on a cone envelope surface. Since a hydraulicdamper in particular is intended only to take up axial loads, in orderto ensure the stability of the actuator unit, a cardan bearing isprovided at least at one fastening point, and ideally a bearing with twodegrees of freedom is provided at both bearing points. Because of thehigh hydraulic forces that are to be transmitted, a conventional cardanbearing with intersecting axes would have to be made very solid. Becauseof the limited installation space, however, provision is made to dividethe cardan bearing and to have the axes not intersect. This affordsadvantages for the design of the joint, since collisions between thehydraulics and a bearing block can be more easily avoided.

It is also possible, at the connection point between the axes, tomeasure the hydraulic force dependent on the knee moment, and thismeasured variable can be used, for example, to control the actuator.With such a joint bearing, it is possible to take up the very highhydraulic forces that occur and at the same time to keep the sizes to aminimum. Alternatively, provision is made for at least one of thebearings to be designed as a ball-joint bearing, in order to obtain, onthe one hand, a low overall height and, on the other hand, a purelypunctiform introduction of axial force into the actuator unit. It isthus possible to eliminate or reduce interfering bending moments, inparticular moments interfering with piston/cylinder hydraulics.

An improved adaptation to the anatomical circumstances is achieved ifthe actuator unit is arranged, in the lateral plane, tilted about adefined angle. In this way, the actuator or hydraulic damper can bemounted lying tightly on the thigh.

In addition to this, or also separately, the foot part can have a dorsalspring, on which or in which at least one sensor is arranged fordetecting the acting forces, for example the bending load, and thus fordetecting the ankle moment. These sensor data can be used to change theaction of the damper unit via an actuator and to change the damping inaddition to the constructive damping characteristics. In the design ofthe actuator unit as a drive or a combination of drive and damper, thedata are used to change the behavior of the actuator unit. Likewise, aknee angle sensor, knee moment sensor and an absolute angle sensor canbe mounted on the orthosis for determining the spatial orientation of atleast of one of the rails. The data from the sensors can be usedtogether or separately for controlling the actuator unit. Such anarrangement of sensors for controlling the resistance moment profiles orthe behavior of the actuator unit can also be used independently of theabove-described geometric arrangement of the actuator unit.

The control means for changing the behavior of the actuator unit iscoupled to the sensors and is used, for example, to change the dampingresistance or the applied force in the actuator unit.

Joint kinematics can be provided via which the actuator unit isarticulated on the thigh and/or lower leg structure. The actuator unitcan also be articulated directly on the thigh and/or lower legstructure, and in both cases provision is made for a pivotability and/ordisplaceability of the joint kinematics or of the actuator unit. Thepivotability or displaceability is in the lateral plane, and thefastening points of the actuator unit, on the thigh and lower legstructure, and the center of rotation of the joint mechanism also form atriangle.

The movement axis of the orthosis between the thigh and lower legstructures can be fixed by the midpoints of two ball joints, if thethigh and lower leg structures are connected to each other by balljoints. Alternatively, the thigh and lower leg structures can also beconnected to each other by a cardan joint.

The pivot angle of the joint mechanism in the lateral plane can be fixedby a medial support joint, which can be a hinge joint, cardan joint orball joint.

The lever between the rotation axis of the joint mechanism and theadjacent fastening point of the actuator unit can be formed by two balljoints coupled via at least one connecting rod.

The method for controlling a knee orthosis with a thigh structure, ajoint mechanism and a lower leg structure, which has a foot part, ischaracterized in that an active moment, in particular ankle moment,within the orthosis is determined, and the resistance of the actuatorunit is changed as a function of the moment, in particular ankle moment.In addition or as an alternative, the actuator unit can be changed as afunction of a measured or calculated knee moment, the knee angle, thatis to say the position of thigh structure and lower leg structure toeach other, or of the spatial orientation at least of a thigh or lowerleg structure. It is possible in this way to control the stance andswing phases in patients with paralysis, in whom the leg is no longercontrollable at will. By means of the modifiable resistance moment, forexample via a hydraulic actuator, every desired knee moment can begenerated, thereby permitting stance phase flexion and alternatingdescent of inclines or stairs. In active actuator units, the movementcan be correspondingly supported in a targeted and efficient manner.

In a development of the invention, the sensor signals generated withinthe orthosis are additionally used to generate impulses for functionalelectrostimulation of the remaining muscles. In this case, the measuredvalues determined by the orthosis are used to establish the strengthand/or timing of the stimulation impulses from a unit connected to thecontrol device and permitting functional electrostimulation. In thisway, the remaining muscles can be activated in a targeted manner inorder to improve the movement profile and to support or replace theactuator device.

An illustrative embodiment of the invention is explained in more detailbelow with reference to the attached figures, in which:

FIG. 1 shows a schematic side view of a knee-ankle-foot orthosis in sideview;

FIG. 2 shows a schematic representation of the orthosis in a front view;

FIG. 3 shows an orthosis device in a view from the dorsal direction;

FIGS. 4 a and 4 b show schematic representations of the orthosis whenstanding and sitting;

FIG. 5 shows a diagram of the arrangement of the actuator unit;

FIG. 6 shows a profile of the moment over the knee flexion;

FIG. 7 shows positions of the actuator unit at different flexion angles;

FIG. 8 shows a variant of FIG. 1;

FIG. 9 shows a sensor on a substrate plate;

FIG. 10 shows an example of the arrangement of sensors according to FIG.9 in a connection element;

FIG. 11 shows a variant of the sensor according to FIG. 9; and

FIG. 12 shows an example of the arrangement of the sensor according toFIG. 11.

In FIG. 1, an orthosis device 1 in the form of a knee-ankle-footorthosis is shown in a schematic representation. The orthosis device 1has an upper part 2 in the form of a thigh structure, and a lower part 3in the form of a lower leg structure. The thigh structure 2 and thelower leg structure 3 are connected to each other via a joint mechanism6 so as to be able to pivot about a joint axis. A foot part 4 is securedto the lower leg structure 3 via a connection element 5. The connectionelement 5 is arranged in a receiving means 9 located on the dorsal faceof the lower leg structure 3.

The thigh structure 2 is composed of a main body in the form of areceiving shell, which can be secured to a thigh by fastening means 21.The fastening means are, for example, buckles, clasps or hook-and-loopfasteners, which can be placed across an opening within the thighstructure 2 and thus close the thigh structure 2. The opening can befrontal or dorsal. Fastening means 31 are likewise arranged on the lowerleg structure and can be closed frontally below the knee joint aroundthe lower leg.

The joint mechanisms 6 can be arranged both medially and laterally onthe orthosis device 1, and the thigh structure 2 and the lower legstructure 3 are secured to the joint mechanism 6 by joint structureelements 62, 63. A control device 8 for controlling an actuator unit 7is arranged on the lower leg structure 3 and, on the basis of a programand various sensor data, changes parameters within the actuator unit, inorder thereby to increase or decrease the damping or to adjust theapplied force. As an alternative to arranging the control unit 8 on thelower leg structure 3, it can also be arranged on the thigh structure 2.The actuator unit 7 is designed as a hydraulic or pneumatic actuatorunit with a piston and a cylinder. In the illustrative embodiment shown,the proximal end of a piston rod is arranged at an upper attachmentpoint 72 on the thigh structure 2, and a lower attachment point 73 of anactuator housing is arranged as the distal bearing point of the actuatorunit 7 on a proximal end of the lower leg structure 3, in the area ofthe lower joint structure elements 63. The foot part 4 can be designedin one piece with the connection element 5 and can be securedreplaceably in a receiving means 9 on the lower part 3, or theconnection element 5 can also be secured to a separately formed footpart 4. The connection element 5 can also be formed in one piece withthe lower leg structure 3.

In the illustrative embodiment shown, the actuator unit 7 is arrangedonly on the lateral side of the orthosis device 1, as an alternative toa lateral and medial arrangement of two joint mechanisms 6, ifappropriate with two actuator units 7.

In FIG. 2, the orthosis device 1 according to FIG. 1 is shown in a frontview. It will be seen here that the thigh structure 2 is composed of ashell-shaped main body 20, on which fastening means 21 in the form ofstraps are arranged. The lower leg structure 3 is correspondinglyprovided with a main body 30, which can be secured by the fasteningmeans 31 to the lower leg (not shown) of a person wearing the orthosis.An orthosis device 1 for a right leg is shown in FIG. 2, and the jointmechanism 6 is arranged laterally on one side of the orthosis device 1.It can also be seen from FIG. 2 that the main bodies 20, 30 of the thighstructure 2 and lower leg structure 3, respectively, are closeddorsally.

In FIG. 3, the orthosis device 1 is shown in a rear view. Extendingthrough the joint mechanism 6 is a joint axis 60, which is flush with ananatomical rotation axis of compromise and about which the upper part 2and the lower part 3 are mounted so as to pivot relative to each other.The joint axis 60 is shown horizontally in FIG. 3, which in realitywould only exceptionally be the case. The actuator unit 7 is arrangeddirectly on the thigh structure 2. It will be seen from FIG. 3 that thelongitudinal course of the actuator unit 7 is at an angle θ to thevertical, such that the axes of the proximal and distal attachmentpoints 72, 73 of the actuator do not run parallel to the knee axis. Thisangle θ corresponds to the ilio-tibial angle about which the actuatorunit 7 has to be pivoted out of the sagittal plane. The pivot axis runsin the anterior-posterior direction. The ilio-tibial angle θ can be upto 30°, depending on the manner of securing and on the anatomy of theorthosis wearer.

FIGS. 4 a and 4 b show a schematic representation of an applied orthosisdevice 1, in a standing position in FIG. 4 a, and in a seated positionin FIG. 4 b. The orthosis device 1 is shown in a simplified manner witha thigh rail 22 and a lower leg rail 32, which are mounted so as to bepivotable relative to each other about the joint mechanism 6. The thighrail 22 is secured to the thigh by a corresponding fastening means 20,while the lower leg rail 32 is secured to the lower leg by thecorresponding fastening means 30. The thigh rail corresponds to thethigh structure, while the lower leg rail corresponds to the lower legstructure. The actuator unit 7 is arranged laterally and dorsally withrespect to the rails 22, 32, the upper fastening point 72 of theactuator unit 7 being arranged on the thigh rail 22, and the lowerfastening point 73 of the actuator unit 7 being arranged on the lowerleg rail 32. The joint mechanism 6 at the same time forms the center ofrotation of the two rails 22, 32 with respect to each other. The lowerfastening point 73, which forms the distal bearing of the actuator unit7, is at a distance in the dorsal direction from the center of rotationof the joint mechanism 6, this distance being embodied via an obliquelydownwardly directed lever. In the embodiment shown, the fastening point73 of the actuator unit 7 lies below the center of rotation of the jointmechanism 6 when the lower leg rail 32 is perpendicular.

FIG. 4 b is a schematic representation of the state when an orthosiswearer is seated with the orthosis fitted. The angle between the thighrail 22 and the lower leg rail 32 is greater than 90°. It will be seenfrom FIG. 4 b that the actuator unit 7 is arranged laterally alongsidethe thigh of the orthosis wearer. It is thus possible for the leg to becompletely flexed without the actuator unit 7 getting in the way.Likewise, with such an arrangement of the actuator unit 7, the orthosisis not bulky, which means that the orthosis can be worn inconspicuously.In FIGS. 4 a and 4 b, the foot part for supporting the foot is notshown. It is also possible, in principle, for the orthosis 1 to beprovided without a foot part.

FIG. 5 shows the basic geometric arrangement of the actuator unit 7 onthe rails 22, 32. The hydraulic piston is mounted at its upper end onthe upper bearing point 72, for example in a ball-and-socket bearing. Atthe lower end of the actuator unit 7, it is supported at the lowerbearing point 73, which is coupled to the lower leg rail 32. The thighrail 22 and the lower leg rail 32, or the upper part and the lower partof the orthosis device, are coupled to each other in the joint mechanism6 so as to be able to pivot about a joint axis. The fastening point 73of the lower bearing is offset dorsally by the distance l_(H) inrelation to the center of rotation or axis of rotation of the jointmechanism 6, such that the two fastening points 72, 73 and the center ofrotation of the joint mechanism 6 form a triangle. The side between thelower fastening point 73 and the center of rotation 6 is at an angle Φ₀of ca. 30° with respect to the side formed between the upper fasteningpoint 72 and the center of rotation 6, when the orthosis device 1 isextended. It is only after the thigh structure 2 or the thigh rail 22has pivoted about an angle corresponding approximately to Φ₀ in thedirection of flexion that the actuator unit 7, or the side between theupper fastening point 72 and the lower fastening point 73, isperpendicular to the connecting line l_(H) between the lower fasteningpoint 73 and the center of rotation of the joint mechanism 6. The leverl_(H) between the rotation axis of the joint mechanism 6 and theadjacent fastening point 73 of the actuator unit 7 can be embodied bytwo ball joints coupled via at least one connecting rod. This angle Φ₀lies between 0° and 90°, in particular between 10° and 90°, andpreferably between 30° and 90°, and is chosen such that it correspondsto the angle at which the maximum knee moment between the thigh and thelower leg of the orthosis wearer is reached or is intended to bereached. A schematic profile of the knee moment over the flexion angleis illustrated in FIG. 6. An angle of 30° is assumed as the angle Φ₀. Itwill be seen from FIG. 6 that a progressive damping area is present fromthe extended position at 0° up to a flexion angle of 35°, such that,even with a linear configuration of the actuator unit 7, a progressivedamping is achieved on account of the changing geometry. The deviationof the end angle of the progressive damping area from Φ₀ results fromthe change in the lengths of the actuator unit during flexion.

At the start of the flexion, that is to say across the first 35° offlexion, the knee moment increases as far as an angle Φ₀, which arisesfrom the trigonometric relationships and corresponds approximately toΦ₀, until the connecting line between the upper articulation point 72and the lower articulation point 73 is perpendicular to the connectingline between the lower articulation point 73 and the center of rotationof the joint mechanism. On account of the purely axial force that theactuator unit 7 can provide counter to a flexion of the knee, a maximumknee moment is reached when the working axis of the actuator unit 7 isperpendicular to the connecting line between the center of rotation ofthe joint mechanism 6 and the lower bearing point 73. Upon a furtherflexion of the knee, the knee moment decreases about the sine of thefurther pivoting, until there is a return movement of the actuator unit,that is to say when the flexion is greater than 90° plus Φ₀. The kneemoment then increases with the cosine if the action of the cylinder ofthe actuator unit or of the damper has been switched from press to pull.

Three extreme states are shown in FIG. 7. State 1 exists in an extendedposition of the leg. In position 2, pivoting has taken place about theangle Φ, such that the maximum knee moment is reached. In position 3,the working axis of the actuator unit 7 lies on the connecting linebetween the lower bearing point 7 and the center of rotation of thejoint mechanism 6, such that a pivoting angle of 90° plus Φ is reached.In this position, the active knee moment is equal to 0, since no leveris present, and the actuator force extends perpendicularly through thecenter of rotation of the joint mechanism 6.

In addition to the moment profile being influenced on the basis of theconstruction and arrangement of the actuator unit 7 within the jointorthosis 1 and of the special arrangement of the bearing points 72, 73relative to the center of rotation of the joint mechanism 6 or to thejoint axis 60, the damping within the joint orthosis can be controlledon the basis of sensor data. The sensor is preferably arranged in theconnection element 5, which is designed as a dorsal spring, anddetermines the active ankle moment during standing or walking. Thearrangement of the sensor 50 is shown in FIG. 8, which correspondssubstantially to FIG. 1, with the difference that the sensor 50 isarranged on or in the dorsal spring 5, which is designed as connectionelement between the foot part 4 and the lower leg structure 3. Thesensor 50 transmits the data to the control unit 8 via which valveswithin the actuator unit 7 are then actuated. Throttle points canlikewise be made larger or smaller, such that it is possible to achievedifferent flows of fluid and therefore degrees of damping or forcesduring the movement. Damping can also be achieved usingelectro-rheological or magneto-rheological fluids and by a correspondingchange in the viscosity of these fluids.

Such control of the orthosis device 10 makes it possible, particularlyin patients with paralyses, in whom the leg is present but can no longerbe controlled at will, that the stance phase and swing phase can becontrolled while walking. By virtue of the hydraulic actuator principlein particular, it is possible to generate any desired knee damping orflexion moment, thus permitting a stance phase flexion and alternatingdescent of inclines or stairs and active support of the movement. Forthe acceptance of such an orthosis device, it is important, in additionto functionality, that its design makes it as inconspicuous as possible,and, in particular, the extent of the orthosis device 1 in themediolateral direction must be minimized as much as possible.

The sensor 50 for determining the active forces in the connectionelement 5, particularly for determining the ankle moment, can beintegrated in the connection element 5. FIG. 9 is a schematiccross-sectional view showing the design of a sensor 50 with a straingauge 51, which is secured on a substrate, in particular a metalsubstrate 52. The strain gauge 51 is secured in a conventional manner onthe substrate 52, for example adhesively bonded, and is screened offfrom the environment by separating layers 52. The separating layers 53are fixed on the substrate 52 and can be composed, for example, of aseparating film or a silicone encapsulation or coating. These separatinglayers 53, which are arranged on the top and also on the underside ofthe substrate 52, avoid shearing forces being transmitted to thesubstrate 52 and to the strain gauge 51 secured thereon. Providedlaterally alongside the separating layers 53, connection areas 54 of thesubstrate 52 are provided at which the substrate 52 can be connected tothe surrounding composite material. These connection areas 54 come intocontact with the binders of the fiber composite material and thusestablish a connection to the fiber materials.

FIG. 10 is a schematic side view of the connection element 5 in the formof a bar spring element, for example. A sensor 50 with a screened-offstrain gauge 51 on a substrate 52 is laminated in on each side of theneutral fiber 55. Cables 56, which are connected to the strain gauge 51,lead from the connection element 5 to an evaluation unit or the controldevice 8. The substrate 52 is preferably thin, for example between 0.1mm and 0.5 mm, such that the whole arrangement of the sensor 50 with thestrain gauges 51 and separating layers 53 has a thickness of less than 1mm. The sensitivity of the sensors can be adjusted by the positioninside the connection element 5, the change arising from the variationin the distance from the neutral fiber 55.

FIGS. 11 and 12 show a variant of the invention in which strain gauges51 are arranged on both sides on the substrate 52 and are surrounded byseparating layers 53. Here too, connection areas 54 are providedalongside the separating layers 53 in order to be laminated into theconnection element 5. FIG. 12 is a sectional view showing thearrangement of the sensor 50 according to FIG. 11 inside the connectionelement 5. The sensor 50 is arranged in the neutral fiber 55 of theconnection element 5, and the cables 56 lead from the connection element5. The substrate 52 bends together with the connection element 5 andgenerates an output signal. Because the strain gauges 51 are arrangeddirectly adjacent to the neutral fiber 55, a high amplification factoris needed, but there is the advantage that only a single foreign bodyhas to be arranged inside the composite material element 5. This foreignbody in the form of the sensor 50 can be easily inserted and laminatedin as a completely prefabricated module, which optionally contains anelectronic circuit for signal amplification and signal processing.

The connection element 5 is designed as a dorsal spring in order toincrease the energy efficiency for the orthosis wearer. Like the footpart 4 applied thereto or formed integrally thereon, the dorsal spring 5can also be composed of a fiber-reinforced, elastic structure, forexample a carbon structure, which absorbs the energy of the contact atheel strike and, upon initiation of the swing phase, releases theabsorbed energy, as a result of which the initiation of the swing phaseis made easier. By measurement of the deformations within the dorsalspring 5 by the integrated sensor 50 or by several integrated sensors,which can also be integrated in the foot part 4 analogously to theintegration within the dorsal spring 5, it is possible, from the directmeasurement of the deformations within the structures, to drawconclusions regarding the position of the body and the intended movementof the patient. On the basis of the determined sensor data, for exampleof the ankle moment or of the loads and load directions acting insidethe respective structure, it is possible to make various adjustments inthe actuator unit 7. Various states of the damping or of the drive areswitched, wherein the state transitions are carried out as a function ofthe sensor signals within the dorsal spring 5 and, if necessary, of aknee angle sensor. The knee angle, that is to say the flexion anglebetween the thigh structure 2 and the lower leg structure 3, can bedetermined either by an angle-measuring device, arranged directly on thejoint mechanism 6, or with the aid of sensors which measure the positionof the respective components relative to a directional componentindependent of the orthosis, for example relative to the force ofgravity component or to the horizontal. Likewise, sensors can beprovided for measuring knee moments or axial force loads, in order tofurther improve the control possibilities of the actuator unit.

During the rollover movement of the foot when walking, the ankle momentruns through a typical time profile during the stance phase. In thecourse of the rollover movement, the spring element 5 is initiallydeformed, i.e. “charged” with energy, after which the spring 5 relaxesagain, i.e. energy is output. Analogously to this, there is a typicalprofile for the knee angle and for the knee moment, and this profile canbe influenced via the actuator unit 7, in particular via the actuatorhydraulics, as a result of which the time profile of the energy storedin the spring 5 can also be influenced within certain limits.

The actuator unit 7 is preferably equipped as a linear hydraulic damperunit. The damping can be adjusted via two valves separately forextension and flexion, the valves being adjusted via servo motors and anoptionally interconnected gear. The receiving shells 20, 30 of the thighstructure and lower leg structure 2, 3, respectively, are likewisepreferably made of a carbon fiber material, so as to be able to take uphigh forces without requiring a large format and without making theorthosis device 1 too heavy. The actuator unit 7 generates brakingmoments, with kinetic energy being converted into heat. With theorthosis device 1, it is possible to walk on the level at differentspeeds, to climb inclines or stairs with different gradients and toadopt different seated positions. Different operating modes can be setvia corresponding operating elements on the orthosis device 1, forexample by remote control or a PC interface, which can be used to callup different programs stored in the control unit 8. In a similar way,necessary software can also be loaded onto the control unit 8 ormodified by an orthopedic technician.

1-20. (canceled)
 21. A method for controlling a knee orthosis,comprising: providing a thigh structure, a lower leg structure, anactuator unit arranged between the thigh structure and the lower legstructure; providing fastening points for the fastener unit on the thighstructure and on the lower leg structure; securing the thigh structureto a thigh with a first fastening member; pivotably coupling the lowerleg structure to the thigh structure via a joint mechanism; securing thelower leg structure to a lower leg with a second fastening member;forming a triangle among the fastening points and a center of rotationof the joint mechanism; determining an active ankle moment within theorthosis; changing a behavior of the actuator unit as a function of atleast the ankle moment.
 22. A method according to claim 21, wherein thefastening points are arranged on the thigh structure and lower legstructure such that a connecting line between the fastening points isperpendicular to a connecting line between one of the fastening pointsand the center of rotation in an angular position of a knee in which thelower leg is bent at an angle of between 0° and 90° relative to thethigh.
 23. A method according to claim 21, wherein the actuator unit andthe fastening points of the actuator unit are mounted so as to bemovable or pivotable in a lateral plane.
 24. A method according to claim21, wherein the lower leg comprises a foot part having a dorsal spring,on which or in which at least one sensor is arranged for detecting theankle moment.
 25. A method according to claim 21, wherein the actuatorunit comprises a linear hydraulic damper unit.
 26. A method according toclaim 25, further comprising adjusting damping provided by the linearhydraulic damper unit via two valves separately for extension andflexion, the valves being adjusted via servo motors.
 27. A method forcontrolling a knee orthosis, comprising: providing a thigh structure, alower leg structure, an actuator unit arranged between the thighstructure and the lower leg structure; providing fastening points forthe actuator unit on the thigh structure and on the lower leg structure;securing the thigh structure to a thigh with a first fastening member;pivotably coupling the lower leg structure to the thigh structure via ajoint mechanism; securing the lower leg structure to a lower leg with asecond fastening member; forming a triangle among the fastening pointsand a center of rotation of the joint mechanism; measuring orcalculating a knee moment; changing a behavior of the actuator unit as afunction of the knee moment.
 28. A method according to claim 27, whereinthe fastening points are arranged on the thigh structure and lower legstructure such that a connecting line between the fastening points isperpendicular to a connecting line between one of the fastening pointsand the center of rotation in an angular position of a knee in which thelower leg is bent at an angle of between 0° and 90° relative to thethigh.
 29. A method according to claim 27, wherein the actuator unit andthe fastening points of the actuator unit are mounted so as to bemovable or pivotable in a lateral plane.
 30. A method according to claim27, wherein the actuator unit comprises a linear hydraulic damper unit.31. A method according to claim 30, further comprising adjusting dampingprovided by the linear hydraulic damper unit via two valves separatelyfor extension and flexion, the valves being adjusted via servo motors.32. A method for controlling a knee orthosis, comprising: providing athigh structure, a lower leg structure, an actuator unit arrangedbetween the thigh structure and the lower leg structure; providingfastening points for the actuator unit on the thigh structure and on thelower leg structure; securing the thigh structure to a thigh with afirst fastening member; pivotably coupling the lower leg structure tothe thigh structure via a joint mechanism; securing the lower legstructure to a lower leg with a second fastening member; forming atriangle among the fastening points and a center of rotation of thejoint mechanism; changing a behavior of the actuator unit as a functionof a spatial orientation of the at least one of the thigh structure andthe lower leg structure.
 33. A method according to claim 32, wherein thefastening points are arranged on the thigh structure and lower legstructure such that a connecting line between the fastening points isperpendicular to a connecting line between one of the fastening pointsand the center of rotation in an angular position of a knee in which thelower leg is bent at an angle of between 0° and 90° relative to thethigh.
 34. A method according to claim 32, wherein the actuator unit andthe fastening points of the actuator unit are mounted so as to bemovable or pivotable in a lateral plane.
 35. A method according to claim32, wherein the actuator unit comprises a linear hydraulic damper unit.36. A method according to claim 35, further comprising adjusting dampingprovided by the linear hydraulic damper unit via two valves separatelyfor extension and flexion, the valves being adjusted via servo motors.